Interesting, thanks for posting. I had a first look and think that the AI has messed up with the floating-point and casting instructions (i.e. just copied over the RV instructions). I also spotted other places (e.g. TLS) which look like RV. It's also surprising that the code - as you say - is so much slower than (optimized?) GCC, since QBE is assumed to be at 70-80%.